Hi everyone, I described the reflink operation at the Linux Storage & Filesystems Workshop last month. Originally implemented as an ocfs2-specific ioctl, the consensus was that it should be a syscall from the get-go. Here's some first-cut patches. For people who have not seen reflink, either at LSF or on the ocfs2 wiki, the first patch contains Documentation/filesystems/reflink.txt to describe the call. The short-short version is that reflink creates a reference-counted link. This is a new file that shares the data extents of a source file in a copy-on-write fashion. The second patch adds iops->reflink() and vfs_reflink(). People interested in LSM interaction, please look at my comments in the patch header and the implementation of vfs_link(). I think it needs improvement. The last patch defines sys_reflink() and sys_reflinkat(). It also hooks them up for x86_32. The final version of this patch will obviously include the other architectures. The patches are also available in my git tree: git://git.kernel.org/pub/scm/linux/kernel/git/jlbec/ocfs2.git reflink The current ioctl-based implementation for ocfs2 is available in Tao's git tree at: git://oss.oracle.com/git/tma/linux-2.6.git refcount It will be reset atop the system call very soon. Please send any comments along. Joel Documentation/filesystems/reflink.txt | 129 ++++++++++++++++++++++++++++++++++ Documentation/filesystems/vfs.txt | 4 + arch/x86/include/asm/unistd_32.h | 1 arch/x86/kernel/syscall_table_32.S | 1 fs/namei.c | 96 +++++++++++++++++++++++++ include/linux/fs.h | 2 6 files changed, 233 insertions(+) -- "But then she looks me in the eye And says, 'We're going to last forever,' And man you know I can't begin to doubt it. Cause it just feels so good and so free and so right, I know we ain't never going to change our minds about it, Hey! Here comes my girl." Joel Becker Principal Software Developer Oracle E-mail: joel.becker@xxxxxxxxxx Phone: (650) 506-8127 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
